| 摘要 |
PROBLEM TO BE SOLVED: To provide a malfunction preventing method and circuit by which noise can be masked by using the frequency of a clock signal, which is higher than the frequency of an input signal. SOLUTION: A buffer 1 detects the logic level of an input signal 101 and outputs a signal 102 which is waveform-shaped. A first edge detection circuit 2 holds the logic level outputted when the change point of the signal 102 outputted from the buffer 1 is detected. A second edge detection circuit 3 starts counting when the first edge detection circuit 2 detects the change point and outputs a reset signal 105 when it counts the number (m) of the change points of a clock signal 103 whose frequency is n-times as much as the input signal 101, which is previously set. Thus, noise mixed at the start time of the input signal 101 is masked by the setting and the resetting of the first edge detection circuit 2 and the second edge detection circuit 3 by the signals outputted from them. |
